IAASB retires greenhouse gas reporting assurance standard

The International Auditing and Assurance Standards Board (IAASB) has retired its assurance standard for greenhouse gas reporting following the publication of a new standard on generic sustainability assurance.

The International Standard on Assurance Engagements (ISAE) 3410, called ‘Assurance Engagements on Greenhouse Gas Statements’, will be withdrawn by the end of next year. Greenhouse gas reporting assurance will instead be included in the 2024 International Standard on Sustainability Assurance (ISSA) 5000, ‘General Requirements for Sustainability Assurance Engagements’ – which is effective for information reported on or after December 15, 2026.

“ISSA 5000 addresses assurance of all types of sustainability information, including greenhouse gas emissions, regardless of how that information is presented,” IAASB said in a statement.

Improving sustainability assurance market

IAASB’s latest decision forms part of a general effort to strengthen the sustainability assurance market, which is growing as a result of increasing sustainability reporting obligations for companies. 

In January 2025, IAASB and the International Ethics Standards Board for Accountants (IESBA) made their respective standards, ISSA 5000 and IESSA, interoperable in an “important evolution in global sustainability reporting and assurance”. 

Tom Seidenstein, Chair of the IAASB, said: “These standards establish the necessary technical and ethical pillars to ensure that qualified practitioners could consistently perform high-quality assurance engagements on sustainability information.”

Recent research found that the global ESG assurance services market was worth US$1.54 billion in 2022 – and will grow at a rate of 27% per year to US$5.89 billion by 2028, driven by mandatory sustainability disclosures and investor expectations for third-party assurance.

According to the International Federation of Accountants (IFAC) and AICPA & CIMA, 73% of companies obtained assurance on at least some of their sustainability disclosures in 2023.